The present inventive concepts relate to image sensors and, more particularly, to complementary metal oxide semiconductor (CMOS) image sensors including source follower gates disposed in recess regions of a substrate.
An image sensor transforms optical images into electrical signals. Recent advances in the computer and communication industries have led to strong demand for high performance image sensors in various consumer electronic devices such as digital cameras, camcorders, PCSs (Personal Communication Systems), game devices, security cameras, medical micro cameras, etc.
Image sensors may be classified into various types, including a charge coupled device (CCD) type and a complementary metal oxide semiconductor (CMOS) type. CMOS image sensors may have less complicated operating methods and may be minimized by integrating signal processing circuits into a single chip. CMOS image sensors may require relatively small power consumption, which can be useful in devices with limited battery capacity. Additionally, the fabrication cost can be reduced by using CMOS fabrication technologies.